Electrical control apparatus



June 2, 1925. 1,539,885

E. H. THOMPSON ELECTRICAL CONTROL APPARATUS Filed Dec. 10, 1921 3 Sheets-Sheet l FiE. 1

WITNESSESS INVENTOR BY 444; ww

ATTORNEY;

' E. H. THOMPSON ELECTRICAL CONTROL APPARATUS Filed Dec. 10, 1921 3 Sheets-Sheet 2 INVENTOR a o o a um a a u nu 0O 2 9 4 3 0 oo 0& 1 4:-

0 7 I 7 9 4 4 6 Cw 0. M &0 My x. i Q v. a F 3 6 8 .2 .ifi I-t i WITNESSESS ATTORNEYS E. H. THOMPSON ELECTRICAL CONTROL APPARATUS A June 2, 1925- 1,539,885

Filed Dec. 10 1921 3 Sheets-Sheet 3 FIG. 3.

WITNESSESS I g Y IINVENTOR I M: 6142: :VM 1

ATTORNEYS Patented June 2, 1925.

UNITED STATES Y 1,539,885 PATENT OFFICE.

EUSTIS H. THOMPSON; on NEW xENsINe'roN, PENNShZ'LVANIA, assxonon, BY nrneo'r AND MESNE ASSIGNMENTS, 'ro WESTINGHOUSE ELECTRIC & MANUFACTURING ccmANY, A coaroaa'rron or PENNSYLVANIA.

ELECTRICAL CONTROL APPARATUS.

Application filed December 10, 1921. Serial No. 521,385.

To all whom it only concern:

Beit known that I, Itnsrrs H. TnoMrsoN,

a citizen of the United States, and a resident of New Kensington, in the county of Vestmoreland and 5 have invented a .new and usefulImp'roWlincnt in' Elcctrical (ontrol Apparatus, of which the following is a specification.

' Thisinvention relates to an electrical con trol apparatus and has for an object to maintain a'predeterniined electrical condition in the supply line of a generator, regardless of.the purpose for which said supply is used. I

It is a special object of the invention to provide such a control system in which the usualmagnets, switches, and auxiliary devices used in effecting the control are ac-- celerated or speeded up under, certain conditions; thus'securing a highly responsive.

and effective-control. i i

It is common practice in the type oi: control system to which this invention re- 4 lates to use damping devices usually in the form-of dash-pots for the purpose of preventing premature responsiveness duo. to oscillations or fluctuations, caused'by variations due to the mechanical action of the several working parts-small variations of 0 the-main controlcurrcnt and variations of the auxiliary control currents 0 other auxiliary circuits. It has been fou d that sucli v dampingdcvices under severe conditions ofv operation are objectionable as at present employed because of the fact that they produce a dragor undue friction when large fluctuations inthe control circuit occur, preventing a (Flick responsive action of the regulator. 1 "is objection is particularly noticeable when a'dash-pot is used in which I a heavyfrictional adjustment is employed. Another special object of the invention is to provide a system of control in which the abovenol'cdobjcction is overcome, that is. in which the-objectionable retarding action of the damping devices used is neutralizedor destroyed during abnormal variations or fluctuations in the controlled-circuit. 3 'j Itjis also noted. that the sluggishness o1." many known regulating systems employed in connection with electric furnaces is dueinpart to the inertiaof controlling levers and electrodes, the friction of the controltate of Pennsylvania,

ling levers and dash-pots, and over-traveling of the electrodes.

Another object of the invention is to overcome the sluggishnessrlue to the above causes when the invention is embodied in a furnace controlling system.

It is also an object to provide a regulating systemiir which there will be an autornatic compensation or equalization between the several controls when a plurality of theregulators are used in connection with generators operating in parallel with each other in the same system.

It is still a further object to provide a control system having the above advantages and inwhich various safety devices are employcd to prevent damage arising from abnormal conditions in the several devices comprising the system as a whole, so as to render the same able to overcome or withstal'idithe ditlic ulties arising from the most severe conditions encountered in op-' eration.

These and other objects of the invention securinc a compensation between several units when employed in a single system; Fig. 3 a diagrammatic View illustrating the invention embodied in a control for an electric furnace; and Fig. 4 illustrates a modified form of one of the devices used in conjunction therewith.-

In the embodiment of the invention shown in Fig; 1, l designates a generator ,having the leads 2, 3 in which the voltage is tobe maintained substantially constant. A main controllingv magnet 4 is interposed 1n a conductor 5 br dging the leads 2 and 3 and 'will more readily appear from the follow- 'lng description taken inconn'ection with illustrating how the control is employed for also interposed in this conductor is a rheostat,6.and relay magnets 7 and 8, it being obvious mat a change in voltage in the leads 2 and 3 will cause a change in the current in these magnets and consequently vary their pull r The magnet 4 influences the position of the main controlling, switch 9, pivotedat against the tension of spring 11. The switch arm is adapted-to contact terminal 12 or 13 depending upon its direction of movement to com lete a circuit between the auxiliary supply eads 14: and 15when the switch 18 is in closed position, a conductor 17 connecting lead 15 to the switch erm 9,

and conductors 18 and 19, respectively, connecting the terminals 12 and 13 to the said auxiliary leads. interposed in the conductors 13' and 19 are the magnets QO'and for actuating the auxiliary switches 22 id 23 to close the circuit of motor 24 whose iield windin is indicated at 24'. ssid'motor 71 through the gear 25, rack 2-6, gear 2.? and shaft 28 he "lg adapted to more the arm or rheestat- 21'.- in 'orderi'o vary the resistance thefieltl winding 30 of generator 1, and.-

conseguently its voltage,

'lhe switch 22 is connect-led with the motor conductors 32 end 33 and the switch 23 is similarly connected through the conductors and 35. One arm 01' each of the auxiliary switches 22 and 23 is prolonged and is adapted to contact the terminals 31 and when in open position in order to mrt resistance 36 in. a short circuit of the i of motor to produce a rm 8 by means i nag-nets 39 and extremlty or the 1 core sniping" vice in the lorm oi I :1 us having the usual lay-pass l2 controllcd'hy valve 43. v "(lice end of the winding 01 the magnet 39- isconneUted hyconductor ii to a ter- The relutive'st mine and its opposite to a conductor "46 leading-from line 1? thri h a. relay -17 pair of terminals 48 fil'lki 19.

b l ofthewindingof magnet 10 is connected to the terminal 50 and its opposite end to the,

51 against the relay A switch-53. against H both not said CQIlDL be with; the auxil cad '14: by u'cans of conducis adapted toattract the ar- 1 'edto the istemiof valve 453, (Eh-valve llilS to clo 1m=1l-ct,;,the.infiu; ence ofspringti i i I engths of magnet, 1, lays 'i" and 8, and of the springs 11, 54: are such that during the normal op tion the main controlling switch 9 wiii moved to contact the. temninals 12 and One end the switch arm 9 which is counterbalanced by spring 11. 'If the voltage in the leads 2 and 3 increases beyond a predeterminecl amount, magnet 4 lowersthe arm 9 into contact with terminal 13 completing a circuit through conductor 15, switch 16, conductor 1.7,switch 9, conductor 19, magnet- 21 and lead 14:, thus closing auxiliary switch 23 and completing a circuit through motor 24, through conductors 15, 35, 34 back to lead lite cause the motor to increase the resistance in the field of generator 1. This decreases the output of the generator and the voltage in leads 2 and 3 drops'correspondingly and sincethe pull of magnet 1 is also decreased, spring'll moves arm 9' out of means of conductors 15, 33, 32 and '14, which auses resistance to he cut out of field 30 to aise the voltage of generator 1.

During normal operation, as above describech'slight variations or fluctuations are prevented from influencing. the action of switch 9 due to the use of the dash-pot 41,

and the springs 52 and 54 hold switches 51 ,and 53 in their neutral position throughout the cycle of operation as set forth. "Should,

however, a fluctuation slightly above normal occur, relay 7 will be suflicientlyenergized.

to overcome spring 52, and moveswitch 51 into contact with the terminal 50 to'co'mplete a circuit through magnet 40 by means of conductors 15, 46, 55 and '14-. The energiza'tion of magnet 40 therefore aids the pull exerted by 1 agnet 4, and accelerates the movement of switch 9. Likewise should a fluctuation slightly below normaloccur, switch5l will contact 45 and energize mag net 39 through 15, 44, 55 and 14 in which case pull of magnet 39 will assist thespring -11 in accelerating the action of main Incas of a fluctuation'greatly above norvvitch 53 will be brought into play to contact terminal 48 thus also energizing elay 47, the circuit being closed them thrdugh by 15, 46, contact 48, switch 53, condoctors 55 and 14. Energlzation of relay 47 attracts armature 56 to open the by-pass' va1ve'43 of dash-pot 41, thus eliminating all retarding action necessarily incident to its use. In this case the action of switch 9 will be greatly accelerated to quickly bring the system back to its normal working condition. In case of a great abnormal fluctuation below normal, switch 53 contacts at 49 completing the circuit through 15, 46, 49, 53, 55 and 14, thus opening the by-pass of the dash pot in the same manner as in the case of a great fluctuation above normal.

The auxiliary switches 22 and 23 are normally biased to their open position and when in such position contact with terminals 31' and 32 to short Circuit the armature of the through switches 23, 35, 33, auxiliary switch 22, contact 31, resistance 36 and contact 32.,

This produces a dynamic braking effect en the motorf24'to stop it very quickly enever the auxiliary switches are opene thusadding tothe sensitiveness and accuracy of the system.

In the embodiment illustrated in Fig; 2

a generator 60 supplies current through sup- .,.between them-is necessary to prevent one ,umt assuming'more than its proper share.

ply leads 61, 62and '63. Connected to the shaft of the generator 60 is the auxiliary generator 64, and since both are driven .at

the same speed their. outputs will be in pro portion'to their relative capacities, ,th is en; abling the speed of generator 69 to be controlled by variations in the output of the auxiliary generator 64.

The circuit of the generator 64 completed tl\rough -condnctors 65. main control.

in'agnetfiti,rhcostatt'f, line 68, and relays 69and 70.. v p a The main controlling magnet controls the main switch 71,.th e" auxiliary switches 72, 73 and motor 74 in the same manner as in} the previously described embodiment, and it istheretore deemed nnnecessaryto repeat that portionbf the description. The motor 74 however instcadof changing the resist- ,ance in the field winding of the generator moves the throttle valve 75 of the turbine 76. driving the generators 60 and 64, an

emergency speed governor for said turbine being indicated at 77; I

The relay 69 actuatcs a switch 79 adapted to contact at 80 or 81 and the relay 70 likewiseinores a switch'82 contacting at 83 and S4. Leading from the contact 80 is aconductor connected to one end of the winding of magnet 85. the othcrend of which is connected to conductor 86 leading to the auxiliary supply'line 15'. The conta'ct 81 has leading thereto one end of the winding of magnet 87, the other end being connected-to 86. The windings of magnets 88and 89am similarly connected tofthe contacts 83 and 84 respectively, and to the conductor '86. Each of the magnets 85, 87, 88 and 89' is adapted to influence the core 90 attached ,to

the main control lever 71, a dash-pot 91 being connected to said core if desired.

The switch arm 79 isconnected to the lead 14 by conductors 92 and 93 in which is in terposed the relay 94 adapted to actuate the switch 9 1 to short circuit the resistance 95 in the armature circuit of motor 7%. The switch arm82 is similarly connected to lead 14 by conductors 96, 97 and 93 through the relay 98 and controlling switch 99 for short circuiting resistance 10 also in the armature circuit of motor 74.

The compensatingmagmet 101 is placed in series with the secondarywinding of trans former 102. The core otmagnet 101 is connected at 103 to the end of the main switch motor 24, the circuit being completed arm 71. The function of the magnet 101 is ftocause the speed of the generator to either rise or fall asthe load orcurrent in creases, and, as, illustrated, willcause the speed to rise as the current generated increases..

If several units such as shown and de- I scribed are to be operated in parallel. means for compensating and equalizing the same so as to proper ly proportion the totalload A com ensatmg magnet 101 connected in paralle withcompensating. magnet 101 isemployed forsuchpurpose, themagnet- 101' 7 being in series with the secondary conductor of the transformer 102 of the additional unit, the generator supply leads thereof being "indicated atfil' 62 and 63', corresponding to the leads 61 ,to 63, and the switch lerer 71' corresponding to the main switch lever. 71. Theloperation of thiscmbodiment is'as follows: An increase inthespeed of the generator 60 increases the current in its leads 61 to 6 3,. and since the speed of. auxiliary generator ti t increasesin the same ratio as the main generator the pull exerted by the controlling magnet 66 is also correspondingly increased. Should the currentbe increased beyondthe desired amount, magnet 66 will 1owermain switch71, and should it be decreased below "such predetermined amount switch 71 will rise, and'close one of the auxiliary switches 72 or 73..

The lowering of switch 71 and consequent closing of switch7 3 actnates the main motor 74 and through the druin 7.4., and cable 7 4" gradually closes the throttle yalve 7 5 and reduces thespeed of the turbine 7 6 and gcnerator 60 sufiiciently to .main ta;in the preat 8301" 84 and thus cause magnets 88 or 89 on the main switch and thus causes it to be s'peedcd up.

and do not-cause the switches '19 and "2 to be actuated, said switches remaining in their neutral positions, but as soon as a slight abnormal fluctuation in the controlling'current occurs, switch 79 will co i act at 80 or 81, energizing ither magnet or 87, as the case may he, which exerts a pull arm 71 to accelerate its action. Contacting or switch 79, 80 or 81, also completes a circuit through relay 91 to actuate switch 95%, to shot circuit the resistance 95, in the armature of motor 74, Should the fluctuation be greatly ahove'or below normal, switch 82 will be caused to contact "to'he energized, and also causing'relay 98 to be brought into play to short circuit the ad- (litional resistance thelrcverse operation the resistance 1 00 100 iu'the armature circuit of motor 74-. and thus speed up the actuation ot the same. 7

From the above it is obvious that during will he cut in before resistance 95, and thus gradually slow down. the motor previously to the cutting ofi of its supply urrent from an electric furnace which is ed as comprising .fco open-in, a manner SCI1bed.-

- the current inoue unit w 'ing the electrodes 1 12, 113 and 114 such conductors a maingswitch The main switch 118 is normallly heldin closed position by a the leads 1 1 and 15.; If it is desired to regulate the speed so that it will fall as the load increases, the core of magnet 101 may heplaced below the coil, as indicated in dotted'lines, in which case the pull of magnet 101 will supplement the null exerted by magnet 66. i

n case more than onegcnerating unit is. ployed, as previously described, the switch between the compensatingmagnets 101 and 101 is closed, and any change in ill then correspond ingly influence the comgensating magnet in the other units and cause a corresponding change in the controlling and operating de; This assures an equal distributionthe load hetweenthe several units em 'e'l, and as many units can he used in .llel as may he desired. by simply multiying the controll inn; de ices described.

Fig; 3 shows my invention embodied in the preferred use to which the invention is to be applied. The furnace is diagrammatically indicatthe. receptacle containing a conductive charge 111 and havbetween which and the charge arcs are maintained. The electrodes are respectively connected to the supplyconductors 115, 11611116. 117,- having interposed therein 118, and transformer 119.

lever 119' and" lfil.dli 120'pivoted at 121, which isadaptdfto lease the lever 119'and allow the'i isiiiiiiih a; be yummyae i llhe operating motorJQQ and atheismpanying control connections shown in connection with the only, but it is unclerslood arrangement may he u electrodes The eiectn supporting arm end with' piston 1 cylinder ex ui ipw spring 125, the arm b by the cooperation of ihe pm the tit 01 the arm in the cylhider as at 12?. The we 7 and its attached parts coiuu'icrh -bythe weight 123 attached tothe passing over the. shezn'e 15c and, its oiposite end fastened to the 131. The motor 122 is :nechs nected tothe electrode my any or gearing, the drawing shoe: on the motor shaft which rack 131" on arm 1543. The n continuously excited held 132, uectcd through the conductors to the auxiliary supply leads I The nnzin controlling magne'l indicated at 135 and is in series with the secondary winding of transfoimer 136, and aiso arranged in series therewith are the rheostat '13? and the relays 139, anu- 141. ,The main controlling m: "not 135 is adapted to influence the main controlling switch -12 contacting at 143 and 1 and connected to lead 5 by the conductor 145. i The auxiliary switches 1 16 and 1%? are connected by a suitable gearing driving a pair oi'insulated raclr. bars 148 and 149 and meshing with a pinion 150 to insure simultaneous operation, and switches ai'o provided with the stcadying dash-pots 151 and 152 adapted to allowia quick actionnear the end of the movement of the switches in either direction as clearly shown, The switches 146 and 14 7 are adapted to be actuated by the respective magnets 153 and 15 1; Each. of these magnets is equip ied with four; i indings to vary the pull thereof underklifierent conditions of operation.

A conductor 155 leads from the contact 144 and is connected with one windin of magnet 158 and the other end of W1lGlL conmeets with the conductor 156 attached to the lead 14". The three otlrzr windings of 153 are also connected at one end to conductor 156, and at their opposite ends to the res "ctive contacts 167, 158 and 159. Each 0 the fourvwindings of magnet 154 is connected at one end to (3011(11101101 156' and. the opposite ends are connected to the respective contacts 160, 161,162 and 143.v The' relays-141 140-,v and 139 actuate the respeotivo'switchea' 163, 164 3111.165, said "relays and the springs ofthe switches 163 165 ,beinggo designed as to' cause" the windili'gsv-ofjthe magnets 153, 154 to bq fsucat? a;

cessiv'ely energized.

ice

adapted to actuate the respective switches switch 142.

173, 174 and 175 to short circuit the resistances 176, 177 and 178, the resistances 176 and 177 being in the armature circuit of the motor 122, and the resistance .178 in the field thereof.

When the switches 146 and 147 are in their open position, one arm of each switch is adapted to contact at 179 and 180 in order to include a resistance 181 in the short circuit of the armature ofinotor 122 :s in the previously described embodiments.

The compensating magnet 182 is arranged in series with the secondary windingof a transformer 183 connected across the main simply leads to the furnace and also with the resistance184 submerged in the oil of the transformer 119. The core of magnet 182 is connected to the lever. 185, the end of which is adapted to strike the short arm of'the switch lever of the main controlling Connected to respective conductors 186 and 187 and in series therewith are the relay 188 and switch 189. Disposed on the opposite side or latch 120 from relay 188 is the relay 190 in series with the secondary Winding of transformer 191 on the supply lead 115. Mounted on the arm 123 is a contact finger 200 which is adapted to engage the limiting contacts 201 and 202 for short circuiting the armature of the motor 122 upon an extreme movement of the electrode in either direction.

starting, up the furnace,to control the movemcnt of the electrode by hand, switch 209 is thrown to contact the terminals 212 and 213,

cutting out the automaticcontrolling device and substituting the manual conrol. The manual control 18 effected by means of the rocking ofcontact arm 214, connected to lead '14" and adapted to complete the circuit through either relay 215 or 216 as desired to more the switch 217; Movement of switch 217 in one direction completes the armature circuitof the motor 122 causing it tolift the electrode,while movement of the switch 217 in the opposite direction reverses the 110w in the anmature circuit causing it to lower the electrode. i

leads 15 14" are the" is adjusted, the main switclrwill be caused to contact at 143 which completes the circuit through one of the, windings of magnet 154 by means of conductor 145, switch arm 142, contact 143, magnet 154, conductors 156 and 14",, to close auxiliary switch 147:(1105- -ing of switch 147 suppliescurrent to motor 122 through conductor 206, resistances 176 and 177, switch 209, conductors 207, 288, 205 and 14', causingthe same to lift the elec. trode by means of pinion-130', rack 131', and arm 123. As soon as the el'eetrode is lifted sufficiently to reduce the current flowing therethrough to its normal amount, the main switch 142is released and assumes its neutral position. In case the current falls below normal the switch 142 will rise under theinflucncc of itsspring and contact at'l44'energizing one winding of the magnet 153 and causing the auxiliary switch 146 to close the supply current to motor 122 through conductor-204, switch 209, conductors 208, 207, resistances 177 and 176, conductors 203 and 14", lowering the electrode sufficiently to restore normal current. The resistance 211 reduces the speed of motor 122 during such action as-is obviously desirable.

During the above described normal operation the relays 139 to 141,146, 171 and 172 are not sulliciently energized to close their respective switches. Should the current, however, fluctuate abnormally, the relays 141, 1.40 and 139 will be sufficiently energized in the order namedto movethe switches 163 to.I65 against the respective contacts '160 to 162, thus closing the circuit through the several windings of the magnet 154 and accelerating the action of auxiliary switch 147. Should the fluctuation be abnormally low instead of hi the switches163 to 165 will contactat 15% to. 159gand likewise energize the several windings ofthe magnet 153 and closethe auxiliary switch 146. i

. Contacting of. lever 1.63 at 160, also energizes relay 167, which moves switch 173, short circuiting the resistance 176 and 'spwding up the .motor..12 2., Contact of switch 164 at 161 sim larly energizes relay 171,-moving switch 174'and short circuitmg the re sistance'177, which further increases the relay 172 is energized to insert the resistance 1 178 in the field of motor 122. It is thus seen.

that the switches 163 and 173, 161 and 174, and 165 and 175 are actuated in unison, thus securing an acceleration of both the auxiliary switches and of the motor 122 moving the electrodes.

The above. particularly describes the ac- 1 tion of the regulator upon fluctuations above mal due to the switches 163 to 165 contacting at 157 to 159. It is also evident that as the electrode approaches the position to restore normal current t-herethrough the resistances 178 and 177 and 176 will be inserted in the reverse order as above described, so as to gradually slow down the motor 122 and-prevent its overrunning after the proper setting has been secured.

It is also. noted that due to the special byassesprovided near the ends of the dasli-pots 151 and 152 a quick action of the auxiliary switches is secured at the ends of their movement regardless of whether they are open or closed and when both switches are in open position for contacting at 179 and 180 short circuiting of the armature circuit of the motor through resistance 181 occurs.

As long as voltage is maintained in the main supply leads 115 to 117 and the oil of the transformer 119 in which the resistance 184; is submerged, is cool, the magnet 182 is energized to hold lever 185 inthe position shown in the drawings. Should. the voltage fall, or the oil of the transformer become heated, to an extent to greatly increase the resistance 18 1, the spring attached to the lever 155 willcausc it to strike the short arm of switch 142 and move it into contact with terminal 143 and consequently raise the electrode.

The relay 188 is normally energized by current from the auxiliary-supply leads 14 and 15 to hold the latch -1 20-in position to lock the lever 119' into position to maintain the main switch 118 closed. In the event-the current in leads 14 and 15 should fail, the latch 120 under theinfiuence of its spring will release the latch and allow-the main switch to open.

The relay. 190 is in circuit with the sec ondary winding of thetransformer 191 and functions as an overload release. Should the irrent- 1n the main leads rise abnor malty high, relay 190 will overcome the "pull of relay 188 and release the latch120 of the mam switch, the switch 189 is normally closed; If for any reason the current in the main control magnet circuit should rise abnormally hi h,-relay 138 will be energized suflicient y to open switch 189 thus cutting out the relay 188 .and permitting the main-switchto open. f

.such abnormal fluctuation. 1

It the electrode overtravels in either direction, so as to brin the fingcr 200 into contact with the terminals 201 and 202, the

armature otmotor 122 will be short cirn it becomes desirable to move the electrodes by hand, all that isnecessary is to throw the switch 209 to contact at212 and 213. Rocking of member124 to one side actuates themotor 122 to raise the electrode, while rockin to the other side reverses the rotation of the motor and lowers the electrode.

In Fig. 4 is illustrated a modified construction for raising the electrodes in case the voltage should fail in the main supply leads, the magnet 182' corresponding to magnet 1820f Fig. 3. Its core is connected to a lever 220 which moves the arm of rheostat 221 connected in the circuit of the main controlling magnet 135. As long as the magnet 182 is sufficiently energized to lower-lever 220 against the tension of its spring, resistance 221 remains inserted in the circuit of the magnet 135, but as soon as the pull of the magnet 182 decreases sutliciently, it is.de energized and resistance is cut out of 'the circuit, thus increasin the pull of magnet 135 which moves switc 1 arm 142 into contact with terminal 143;

bringing into play the remaining parts of the controlling apparatus, and'raising'the electrode" in the manner previously on:

' plained.

I claim:

1. An electric control comprising an energy supply circuit, means res nsive to normal variations in an electrica condition in said circuit for maintainin such electrical condition therein substantially constant, and means responsive to abnormal variations in the ener "supply circuit for varying the action of he first named means.

2. An electrical control comprising an energy supply circuit, means responsive to normal variations in an electrical condition in said circuit, a member actuated by saii means to maintain the electrical conditionin the circuit substantially constant, and means responsive to abnormal fluctuations therein to accelerate the actuation of said member. 3. An electric control comprisingv anenergy supply circuit, means responsive to an electrical condition in said circuit, a mem-- ber actuated-b said means to maintain the electrical con itiojn in the supply circuit substantially constant, and successively responsive to different degreesof abnormal fluctuations therein, to accelerate the actu-, ation of said member in accordancewith p; 4. An electrical controlcomprising an encrgy supply circuit, means responsive to an electrical condition in said circuit, a switch actuated by said means forcontrolling the circuit to a motor, means operated by said motor for maintaining the electrical con-. dition in the supply circuit substantially constant, means responsive to abnormal flue-- in the supply circuit for aiding said electromagnet in actuating thesaid switch.

6. An electric control comprising an en-v ergy supply circuit, an electro-magnet responsive to an electrical condition in said circuit, a. member actuated by said magnet,

controlling means adapted to maintain the electrical condition in the "energy supply circuit substantially constant, operative con-, nection between the said member and controlling means,magneti'c means responsive to abnormal fluctuations in the supply circuit for varying the effective pull of the said electro-magnet upon said member.

7. An electric control comprising an en orgy supply circuit, an electro-magnet re sponsive to an electrical condition in said circuit, a switch controlled by said magnet, a motor controlled by said switch, means operated by said motor for maintaining'the electrical condition in the energy supply circuit substantially constant, magnetic means responsive to abnormal increases in the supply circuit for aiding said electromagnet, and means responsive to abnormal decreases in the supply circuit for opposing said electro-niagnet.

- 8. An electric control c m rising an energy supply circuit,an eleetro-magnet responsive to an electrical condition in said circuit, a main switch controlled by said magnet, a pair of auxiliary switches controlled by said main switch, a reversible motor controlled bysai'd auxiliary switches, means operated by the motor for maintaining the electrical condition in the energy supply ci'rcuit;substantially' constant, and magnetic means unres" nsive to slight flue tuations, but influence by abnormally great fluctuations in the supply circuit, for, accelerating-,gthc control of said motolx.

'9. An electric-control comprising an en ergy supply circuit, an electro magnet responsive to an electrical condition in said circuit, a switch controlled by said magnet,-'

a motor controlled by said switch, means operated lay-said motor for maintaining the electrical condition in the energy supply circuit substantially constant, magnetic means responsive to abnormal fluctuations in the supply circuit for aiding said electro-magnet in actuating said switch, a compensating magnet also responsive to the electrical condition in the supply circuit for influencing'th'e movement of said switch, a second compensating magnet in parallel with said first named compensating magnet responsive to the electrical condition in a second energy supply circuit, connected in parallel with said first named energy supply'circult so as .to equalize the loadsbetween the two supply circuits. i

10, An apparatus for regulating electric furnaces comprising, an electrode to be shifted, a power circuit for said electrode, an electric" motor operatively connected to said electrode, switching means responsive to variations in the energy in the electrode circuit for controlling and reversing said .motor, and means responsive to abnormal fluctuations in said electrode-circuit for accelerating the action of said switching means. i

electrode, switching means responsive to variations in the energy in the electrode cir+ cuit, for controlling and reversing said motor, means responsive to abnormal tluct uationsin the said electrode circuit for progressively accelerating the action of said switching step by step, and means for simultaneousl, and progressively accelerating the speed of the motor during each of said. steps. i

12. An apparatus for regulating electric furnaces ,con'iprising an electrode to be shifted, a power circuit for said electrode, an electric motor operatively connected to said electrode, switching means for control ling. and reversing said motor, said means con'iprising a main switch and auxiliary switches, an electro-magnet responsive to variations in the energy .in the electrode circuit for actuating said switching means,

electrode in case the mltage thenein; falls beiow a predetermined point. .i i

13. An ap a atus, forregulating electric furnaces comprising an electrode to be shifted, a power circuit for st Lid electrode, a main switch and; transformers therein, an electric motor operatively connected to said lilt electrode, an auxiliary supply circuit for said motor, switching means; for controlling and reversing, the motor, said means com;

prising a main controllingswitchrandfau iili switches, on elsctromagnet responsive to'rariations in the energy in the electrode circuit for actuatin switching means, mczins responsive to scnormai fluctuations in the elecirode circuit tor accelerating the action of said auxiliary switches, means responsive to the voltage in the electrode circuit end to the temperature 6r said transformer to raise the electrode in case either the voltage tells or the. temperature rises abnormally, and'means responsive to the energy of the auxiiiary supply current for opening said main switch when the voltage fails in the said auxiliary supply circuit.

1%. In a regulator system, a power circuit, an electric motor. for controlling said powercircuit, switching means responsive to va riations in the energy of the power circuit :ior controlling and reversing said motor, means responsive to abnormal fluctuations in the energy of the power circuit for progressively accelerating the speed of the motor, and means for progressively decelerating the speed of the motor as the energy condition of the power circuit approaches normal.

15. In a regulator system, a power circuit, an electric motor for controlling said power circuit, switching means responsive to Va i'iations in the energy oi the power circuitfor controlling andreversing said motor, rclay operated means for varying the resist? ance of the motor circuit to progressively accelerate the speed of the motor upon abnormal fluctuations of the ener ,ofthe power circuit and to progressive y decele rate the speed of the motor as the energy condition of the power circuit approaches normal. w

16. In a regulator system, a power ci'r-' 'cuit, an electric motor for controlling said power circuit, switching means responsive to variations in the en'ergyof the power circuit for controlling and reversing saidmotor, electrorcsponslve means for accelerating said switching means step by step'upon an abnormal variation in'the energy of the power circuit, and electro'responsive means masses for accelerating said motor step by step upon an abnormal variation in the energy of the power circuit and for decelerating said motor as the energy of the power circuitap preaches normal.

17. In aregulator system, a, power circuit, an electric motor for controlling said power circuit, switching means responsive to variations in the energy of the power. circuit for controlling and reversing said motor, means for retarding the movement of said switching means, said means being adapted to allow a quick action of said switching means near the end of each movesponsive to an electrical condition in said i circuit, a switch controlled by said magnet, a motor controlledby said switch,'means operated by said motor for maintaining the electrical condition in the supply circuit substantially constant, means responsive to abnormal fluctuations in the supply circuit for accelerating the actuation of said switch,

a compensating magnet responsive to the electrical condition in the supply circuit, a second supply circuit; a second compensat ing magnet in parallel relation to said first named compensating magnet and responsive to the electrical condition in said second "supply circuit, said second supply circuit being connected in parallel relation to said first named supply circuit so as to equalize the loads between the two, supply circuits. In testimony whereof, I sign my name.

nufgsrrs H. THOMPSON. Witness:

EDWIN O. Joan's. 

